About this calculator

Volume of a circular pipe is π × r² × length. Use this to size expansion tanks, estimate flush volumes or work out how much glycol an underfloor heating loop holds.

Formula: V = π × (d/2)² × L

Frequently asked questions

What does the Pipe Volume Calculator do?

Calculate the internal volume of any pipe in litres or gallons. Volume of a circular pipe is π × r² × length. Use this to size expansion tanks, estimate flush volumes or work out how much glycol an underfloor heating loop holds.

Is the Pipe Volume Calculator free to use?

Yes. Every calculator on Calcurly.com is free, works in your browser without sign-up, and can be embedded on your own website.

How accurate is the Pipe Volume Calculator?

Results are calculated in real time using the formula V = π × (d/2)² × L. Treat the output as a well-informed estimate — always cross-check with local regulations, product datasheets, or a qualified plumbing professional before committing to a purchase or a job.

What inputs does the Pipe Volume Calculator need?

Enter values for: Inside diameter (mm), Length (m). Sensible defaults are pre-filled where possible so you can start with a single change.

Can I embed the Pipe Volume Calculator on my own website?

Yes — copy the iframe snippet at the bottom of this page, or use the Embed Generator to customise the size. The embedded version stays in sync with the live calculator on Calcurly.com.